Cover Story: Zhang J Q, Wu Y P, Chen S H, et al. Optimized bow-tie metasurface and its application in trace detection of lead ion[J]. Opto-Electron Eng, 2021, 48(8): 210123

Lead ions pollution is becoming a serious worldwide environmental problem. It will cause harm to human body through food chain. Lead ions with non-biodegradability and high toxicity even at low concentrations can enter human body mainly through food chain, inadvertent intake, skin contact and respiration.Therefore, for the perspective of environmental monitoring and human health, it is important to develop a sensitive, fast and simple technology for detecting lead ions solution. Chen Lin’s Group, from University of Shanghai for Science and Technology, demonstrated a modified bow-tie terahertz metasurface platform containing micron sized cavity with optimized the ratio of the quality factor Q to the effectively low mode volume Veff (Q/Veff) value. When the continuous metal strip width is 25 μm and the gap size is 2 μm, the Q/Veff of the proposed bow-tie terahertz metasurface reaches a maximum of 2.2 μm^-3 at 0.7 THz. The results of lead ion solution detection experiment indicate that the resonance frequency shift shows good linearity to the concentration of lead ion solution and LoD reaches to 0.1 ng/mL.